Hydraulic governors



Dec. 5, 1961 L. J. MOULTQN ETAL 3,011,352

HYDRAULIC GOVERNORS Filed April 21, 1958 INVENTORS L. J. Moo/Jaw 11dBnxTE Q.

HTTOR/VELV atent 3,011,352 Patented Dec. 5, 1961 fiice 3,011,352HYDRAULIC GOVERNORS Lloyd .Iackson Moulton, Mentor, and Donald J.Baxter,

South Euclid, Ohio, assignors to Curtiss-Wright Corporation, acorporation of Delaware Filed Apr. 21, 1958, Ser. No. 729,639 4 Claims.(Cl. 73523) This invention relates to a hydraulic governor or automaticspeed regulator mechanism for engines and/or other machines havingrotary parts, the objects including provisions of a new or improvedhydraulically operating governor having a so-called compensating ortemporary speed reset or speed droop system or mechanism for attainingisochronous governor operation; a simple and effective adjustablepermanent type speed reset mechanism enab ing the basically isochronoushydraulic governor to operate with various readily selectable amounts orpercentages of speed droop; a hydraulic governor unit having either orboth the above types of speed reset mechanisms capable of being made forefiicient operation in extremely small size and so arranged that theunit can operate in any desired position on an engine or other machinewith all working parts of the governor submerged in governor oil atrelatively low and controlled pressure.

The herewith illustrated embodiment of the invention is a governor unitsimilar to those shown by A. Kalin US. patent, Reissue 23,994 dated May3, 1955; A. H. Rodeck and A. G. Massey U.S. Patent 2,623,504 issuedDecember 30, 1952, and B. O. Burritt US. Patent 2,560- 758 issued July17, 1951. In each of thosepatents primary compensation action on thespeed sensing mechanism is a function of governor servo or power pistonmovement and secondary compensation action is, in effect, dissipation ofthe servo-applied compensation force at a variable or adjusted rate. Insuch governors it is desirable that friction forces on the speed sensingmechanism and the movable parts involved in the compensation action beminimized as much as possible. In the Kalin and Rodeck et al. governors,compensating oil in a generally closed system isolated from that of thegovernor servo mechanism and its pilot valve control acts directly upona receiving piston portion of the governor pilot valve, and a yieldablypositioned feedback force storing piston, hereinafter usually called aproportioner piston, is subjected to compensating fluid pressure duringspeed error and which incidentally prevents fluid temporarily trapped inthe compensating fluid passage from opposing free movement of the pilotvalve. The proportioner piston is normally held in a neutral or freelyfloating equilibrium position by a helical spring. It is importantthat'the proportioner piston and its positioning spring be made readilyaccessible for inspection or change of spring force. It is of greaterimportance that the proportioner piston as Well as the governor pilotvalve and its receiving piston portion shall be as free from staticfriction as possible; and a high degree of freedom is obtained bymaintaining continuous relative rotation of mating cylindrical surfacesof the parts. The present invention, as its principal novel features,provides a readily accessible postion for the proportioner piston aswellas a simple and novel means to obtain continuous relative rotationof it in reference to its coacting cylinder, without requirement ofappreciably more cost than is necessarily involved in an effectualarrangement for driving the governor ballhead or speed sensing flyweightmechanism while permitting the ballhead speed to be altered inreferenceto the governor driv shaft speed.

In making the present governor in as compact form as sometimes requiredfor installation and operation on small engines, the governor case isprovided for isochronous operation, with a simple low height sealedcover for the main governor ease, and when it is desired to adapt suchnormally isochronous governor for permanent but adjustable speed droopoperation, this cover is replaced by a different sealed coverarrangement having the principal components of the permanent speed droopmechanism mounted unitarily therewith and so as to be readily removablefrom the governor case Without disturbing any other portions of thegovernor mechanism.

Various objects and novel features of the invention not indicated by theabove discussion will become apparent from the following description ofthe herewith-illustrated embodiment. The essential characteristics aresummarized in the claims.

In the drawing, FIG. 1 is a schematic view showing the preferredarrangement of hydraulically operated parts and associated fluidconnections. FIG. 2 is a plan view of a physical embodiment of thegovernor, a detachable cover of the main case having been removed toexpose the principal rotary parts and others. FIG. 3 is a longitudinalsectional assembly view taken as indicated'by the line 33 on FIG. 2. Themembers shown at the top of FIG. 3 (above terminal shaft K) are shownbroken away along the section indicating line 3a on FIG. 2(complementing the leftward portion only of line 3-3). FIG. 4 is afragmentary sectional detail view taken at line 44 on FIG. 2 and showingthe preferred governor ballhead drive and an important part of thecompensating system. FIG. 5 is a detail sectional view of the preferredpermanent speed droop mechanism, taken along the lines 5-5 on FIG. 3.FIG. 6 is a detail showing a modified needle valve mounting.

The hydraulic governor mechanism generally as shown in FIGS. 1 and/or 3includes a suitably sealed casing A containing a rotary engine speederror detector mechanism B with flyweights B; a speeder spring C,settable for desired engine speed as by a speeder lever (33, FIG. 3) andconnected Speeder plug C; and a pilot valve or valve mechanism D, themovable element of which, as shown, is a rotatable valve plunger E in anon-rotating or fixed valve sleeve E. The pilot valve- D controls theoperating effect of approximately constant pressure fluid (governor oilas supplied by the engine lubricating system or by agovernor-case-controlled pump, not shown, admitted to passage F) on adifferential area type servo mechanism G, represented by lever-connectedpower pistons G and G" and their respective cylinders H and H.

The pistons G and G" act relatively oppositely on governor output orterminal rockshaft K, through unequal length arms of a lever L, asshown, and stiff rods or links L and L" which are self-centering intapered sockets of respective pistons. Supply pressure passage F iscontinuously connected to cylinder H of servomotor piston G, andmovements of the pilot valve determine the direction of operation of theterminal shaft K by controlling admission of pressure fluid to cylinderH and spill offluid therefrom.

In the illustrated equilibrium or neutral position of the pilot valveplunger E, oil is trapped, via passage 3', in contact with power pistonG". That piston, as shown in FIGS. 1 and 2, has a larger diameter thanpiston G and that difference, in conjunction with a calculatedrelatively longer lever connection to terminal shaft K than piston Ghas, enables single-port-control pilot valve action to produce two-waymovement of the terminal shaft K with approximately equal torque in thetwo directions.

In operation, to cause increased engine fuel metering movements of theterminal shaft K (counterclockwise in FIGS. 1 and 3), the pilot valveplunger E (by lowering as in response to diminished engine speed) admitsgovernor oil through passage I to the relatively larger diametercylinder H; and to cause decreased engine fuel movements of the terminalshaft K the pilot valve plunger E J is moved upwardly to spill trappedoil from the cylinder H to sump, as through a port S of the pilot valvesleeve.

In FIG, 1, the hydraulically acting temporary speed droop orcompensation system between the power piston mechanism G and the speedsensitive mechanism B is diagrammatically represented by an actuatingdisplacement pump N operated by the power piston mechanism G; generallyisolated compensation oil passage or duct receiving piston portion P ofthe pilot valve plunger E; yieldably supported and normally stationaryproportioner piston P exposed to pressure in passage 0, and a needlevalve R for reset rate or timing leak-01f adjustment as required toaccommodate the rate of engine response to the amounts of fuelcorrection as well known in the art.

As shown in FIGS. 1, 3 and others, the governor housing or casecomprises a base section 10, main power case and speeder section 11 anda cover 12 (or 12, cf. FIGS. 3 and 4) constituting a fully sealedcontainer for fluid which may fill the entire case and be suitablyregulated to have a uniform but preferably relatively low pressure.Thereby the governor may be operated in any desired position other thanvertically or as illustrated. A governor drive shaft 14, FIG. 3, coaxialwith the pilot valve mechanism, extends through a suitable bearing borein the base section and is rigid or integral with a gear 15 in a cavityin the base section covered by the lower face of main section 11. Thegear 15, as shown by comparison of FIGS. 1, 3 and 4, meshes with a gear17 in the base section 10 and which, as shown in FIG. 4, has a generallycylindrical tubular hub or quill portion 18 extending vertically in aguide bore 18 of case section 11 and carrying a gear 20 rigid therewith,as on splines, not shown, for ready removability (e.g. in event it isdesired to change ballhead driving speed). The gear 20, as shown in FIG.4, is retained in position on the tubular hub 18 by a snap ring 20 andmeshes with a complementary gear 21 rigid with a rotary ballheadassembly or unit 22 which includes gear 21. Unit 22 is readily removablysupported on a stepped diameter journal formation 21' at the top end ofthe fixed or non-rotatable valve sleeve E.

The flyweights B, FIGS. 1 and 3, are preferably supported by theballhead unit 22 on leaf springs 25 suitably secured to a base portionof unit 22 at their lower ends; and the outward and inward radialmovement of the flyweights is transmitted to the pilot valve plunger Bthrough a U-shaped single piece leaf spring 26 secured tightly to theflyweights and extending under a generally rounded surface of abearing-supporting cup member 28 fastened to the top end of the valveplunger E as by a screw 29. The lower support or perch member 30 for thespeeder spring C is held against rotation by the speeder spring anditsspeeder plug C, and an anti-friction hearing assembly 32 isinterposed between the perch 30 and the cup 28.

Speed setting or speeder lever 33 is pivotally supportedorder that thespeed adjusting screw 36 can be readily attached to and detached fromthe associated free end portion of the lever 33 as a function ofmovement of the cover into and out of the illustrated position, areduced diameter lower end portion 36 of the screw enters an open slot38 (FIG. 2) in the lever. The speeder spring holds the lever against ashoulder near the lower end of the screw 36. Speed droop mechanism 40,when provided in the governor as will be described, operates on thespeed setting lever pivot 3-4 to modify the set speed as a function ofservo piston position in a generally well known manner. All parts whichextend through the walls of the case A generally are suitably sealedagainst leakage.

Referring further to the governor compensation system as shown bycomparison of FIGS. 1 and 4, the actuating compensation fluid pumpN canbe made similarly to the pistons and cylinders of servo or power pistonmechanism G, the pump N being shown as a piston 40a connected as by arigid link in the form of a rod 41 to the lever L, the rod having itslower end received in a suitable centering socket in the piston. Piston40a of the actuator pump N has a return spring 42 for upward strokemovement or in the fuel decreasing direction of the terminal shaft K.When the terminal shaft is removed from the casing section 11, theoperating rods L and L of pistons G, G and rod 41 can be lifted throughthe top opening of the casing section 11 exposing all three pistons forinspection or removal upwardly from their chambers. As suggested by FIG.1, the various portions of compensation fluid passage or duct 0 are soformed in the casing section 11 and so related to the pistons 40a, P andP and their working chambers that, when the governor is installed in itsusual upright position, any air or gas trapped in the compensation fluidwill find its Way to the leak-off orifice controlled by needle valve R.In the normal or equilibrium positions of the compensation pistonelements P and P those elements are so related to their respectiveworking cylinders as not to form pockets that could tend to entrain ortrap air or gas bubbles.

Referring to FIG. 4, ports 44 in the tubular hub or quill 18 or gears 17and 20 are connected with duct 0 and intersect relatively enlarged orcounterbore portion 45 in the lower end of the quill wall below thenormal or equilibrium position of proportioner piston P, so thatmovement of that piston cannot close the ports. The lower endofproportioner piston P may be formed with an extension 46 adapted tolimit downward movement of the piston P as by contact with a plug 47closing the lower end of counterbore 45. The proportioner piston P, asshown, is maintained in its free floating position for relative rotationof the piston and its coacting bore by a single non-rotatable coilspring 48 serving as a compression and tension spring as required atdifferent times and having lower end coils 43 suitably attached to astub portion of the piston P and upper coils 48" similarly attached to astub 49 carried on the lower end of a bracket 50. The bracket can, asshown in FIG. 4, be secured as by screws to a side wall of the casesection 11 above the proportioner piston and spring assembly. When thebracket 50 is detached from the case the entire assembly just mentionedcan be readily removed for inspection or, if desired, for replacement ofthe piston-supporting spring 48 with one of'a different rate.

Assuming the governor oil is supplied from an engine driven pump whoseoutput is connected to the interior of the governor case A, the generalinterior or sump portion of the case will be fully charged with governoroil at commencement of engine operation. The oil in the sump isreplenished through the port S during operation of the power pistons. Tolimit the sump pressure at a low level (e.g. 1 or 2 p.s.i. aboveatmospheric pressure) the'base 10 as shown in FIG. 1 is provided with aone way acting valve 52 and loading spring 53, the valve dischargingexcess pressure oil in a direction toward the engine crankcase when thegovernor is operating to control a speed of an engine. A' pressureregulator mechanism of known or suitable type can be used instead.

Referring to FIG. 3, upper left, when iso-chronous governoroperationonly will be required, and the speed droop mechanism 40 is thereforeomitted, the bracket 55 for the fulcrum of the speed setting lever 33 isdirectly attached to the casing 11 as by one or more screws in theposition indicated by broken lines at 56. When the permanent speed droopmechanism 40 is installed the bracket 55 is preferably supportedforvertical movement as on a rod 58 secured to the casing by a bracket orguide member 59 fastened to the lower end of the rod 58. A coil spring60 around the rod then acts upwardly against the bracket or guide 55tending to raise the speeder lever 33. In that case the terminal shaft Koperates through mechanism to be describedcontinuously to oppose theupward force of the spring 60 tending to raise the speeder lever 33.

As shown particularly in FIGS. 3 and 5, upwardly extending arm portions55' of the bracket 55 support a horizontal pivot or fulcrum pin 62 for aspeed droop lever 64 which, at one end, extends over the terminal shaftK and carries a roller 65 for contact with a suitably contoured cam 66on the terminal shaft. A speed droop adjustment bracket 67 slidablysupported on the underside of the cover 12 carries a shiftable pivot orfulcrum for the speed droop lever 64 in the form of a pin or bolt 68adapted to slide along a slot 70 in the lever 64 from a position such asillustrated in FIG. 3 to various positions along the slot including aposition (not shown) wherein the axis of the pivot pin 68 coincides withthat of the fulcrum pin 62. With the pin 68 in the illustrated position,increase-fuel or counterclockwise movement of the terminal shaft Kallows the spring 60 to raise bracket 55 and reduce the effective forceof the speeder spring C; and the opposite, fuel decreasing, movement ofthe terminal shaft has the reverse effect as common in speed drooplinkages. When the pins 62 and 68 are positioned in mutual alignment thegovernor is conditioned for isochronous or zero speed droop operation.

For adjusting the position of speed droop mechanism pivot pin 68, thespeed droop bracket 67 is connected to a plate 71 on the cover 12 as bya clamping bolt and nut assembly 71', 72 movable along a slot 73 in thecover parallel to the longitudinal extent of the lever 64. Suitablegraduations, not shown, are provided on the slide plate 71, as in region75 thereof, FIG. 5, for association with an index mark (not shown) onthe cover. The support for the fulcrum pin 62 in the arms 55 of bracket55 preferably comprises open slots in respective bracket arms. Therebythe speed droop mechanism with exception of portions permanently carriedby the bracket 55 can be lifted off with the cover 12; and upwardmovement of the cover also lifts the speed adjusting screw 36 out ofoperative association with the speed adjusting lever 33. An O-ring seal77 occupying (e.g.) a circular groove in the top of the cover 12cooperates with the lower face of the slide plate 70 to block leakage ofgovernor oil through the slot 73.

As shown in FIG. the position of a stem portion of the needle valve R isshown in relation to. a plug 78 of the cover 12. This arrangement, withthe plug removed, enables access to the needle valve for adjustment ofcompensation fluid leak-off rate. When the governor is expected to beused in positions other than vertical, the alternative needle valvemounting in the cover according to FIG. 6 is preferred. Needle valvestem R in FIG. 6 has a cylindrical enlarged diameter portion 80extending through an O-ring seal 81 in cover 12; and, above the portion80, the stem is reduced at 82 and adapted for engagement by an adjustingtool. When the cover 12' is removed for inspection or service to thegovernor, the enlargement at 80 relative to the portion 82 protects theseal 81 from being damaged in case operation of the adjusting tool hasroughened the portion 82.

We claim:

1. A normally isochronous hydraulic speed governor unit including acentrifugal speed-error-detecting device, a hydraulic servo or powerpiston mechanism, and a pilot valve plunger operated by thespeed-error-detecting device to control fluid for-operation of saidmechanism, a main casing for said unit having a removable cover, thespeed-error-detecting device including a coiled speeder springoperatingly connected to the pilot valve plunger and whose axisintersects the cover, and a speeder lever connected between its ends tothe speeder spring and operated about a normally fixed fulcrum at one ofsaid ends to set speed, characterized in that the fulcrum is springbiased for movement toward the cover on a guide member carried by themain casing member, a speed droop lever disposed generally parallel tothe speeder lever has a fixed pivotal connection with the guide memberatone end of the speed droop lever and is operated upon at its oppositeend as a function of power piston movement to swing the speed drooplever, a speed droop adjustment bracket is slidably mounted on the coverand is connected to support the speed droop lever on the cover throughthe intermediary of 'a' pivot pin carried by the bracket and movablealong a longitudinal slot in the speed droop lever thereby to establisha variably positionable second pivot or fulcrum for the speed drooplever intermediately of its ends capable of being moved along the slotinto coincidence with said pivotal connection between the guide memberand speed droop lever for zero speed droop, and the pivotal connectionbetween the speed droop lever and said guide member can be establishedand disestablished solely by movement of the cover onto and off the maincasing member.

2. The governor mechanism according to claim 1 including a speed settingscrew carried by the cover and having an operating connection with thespeeder lever which can also be established and disestablished by saidmovement of the cover.

3. A hydraulic isochronous governor having a pilot valve including avalve plunger, speed responsive means connected to operate the valveplunger axially, and a servo motor hydraulically connected for controlby axial movements of the valve plunger, a hydraulic compensation systemcomprising means defining a generally closed compensation fluid passagehaving a generally horizontally disposed portion with a leakofi orificein a top wall thereof connecting the passage with a fluid storage spaceat low pressure, a piston rigid with the pilot valve plunger exposed topressure in the passage, a compensation fluid pump connected foroperation by the servo motor to pro duce pressure changes in thepassage, an upright tubular member having a single axial bore with asmaller diameter portion defining a proportioner piston cylinderentirely above the passage, the bore having a larger diameter orcounterbore portion therebelow with a lateral port intersecting its topend and communicating with the passage, a proportioner piston having acylindrical lower end portion slidably sealing said smaller diameterportion, and two-way acting spring means connected yieldably to supportthe piston during steady state operation of the governor in a positionsuch that the lower cylindrical end portion of the piston lies below thetopmost wall surface of the port.

4. A- normally isochronous hydraulic speed governor unit including acasing, a centrifugal speed-error-detecting device, a hydraulic servomechanism, a pilot valve, including a valve plunger connected foroperation by said device to control fluid for operation of saidmechanism, a drive shaft for the governor connected to drive said devicethrough at least two gears, one coaxial with said device and the otherhaving it axis offset from the rotational axis thereof, said other gearhaving an elongated tubular hub with an axial bore providing a pistonchamber open at one end and generally closed at the opposite end, acompensation fluid passage in the casing including a leakofi-orifice, apump connected for operation by the servo mechanism to produce pressurechanges in the passage, pressure sensitive means on said valve plungerexposed to pressure in the passage, a port in the wall of the tubularhub connecting the generally closed end of said bore to the compensationfluid passage, a proportioner piston slidable in said bore and exposedat one end thereof to the fluid pressure of said passage, a helical coilspring extendthe casing and connected to the other end of the spring insuch manner that the piston is non-rotatably and yieldably held axiallyin a predetermined normal position in said bore during steady stateoperation of the governor unit, the generally closed end of said boreincluding a counterbore portion intersected by said port and extendingbeyond the port away from said normal position of the proportionerpiston so that the proportioner piston cannot close the port by movingpast it.

2,333,184 Kalin Nov. 2, 1943 8 Kalin Feb. 8, Reg git) DEC; 12, KalinApr. 5, Burritt July 17, Parker Aug; 21, Moulton Dec. 23, Moulton Sept.1, Feilden Apr. 13,

